Armed robberies surged 54 percent in New Orleans from 2010 when there were 704 armed robberies to 2015 when there were 1,085. Robberies can be separated into two categories:  armed robberies (where a weapon is present or implied) and simple robberies where no weapon is used.

Breaking down robberies in New Orleans using Calls for Service shows armed robberies are down about 11 percent in 2016 relative to 2015, but overall robberies are virtually unchanged because of a rise in simple robberies. Further investigation reveals the ratio of armed to simple robberies in 2015 was much larger than expected and 2016 appears to have returned to a more “normal” distribution. This has led to a drop in armed robberies and a rise in simple robberies.

There have been 8,063 armed and simple robbery incident Calls for Service that received a ‘Report to Follow’ (RTF) disposition from NOPD from the beginning of 2010 through September 9, 2016. Of those incidents, 64.5 percent were armed robberies or carjackings and 35.5 percent were simple robberies or carjackings (no weapon).

This ratio tends to vary over time though it tends to hang out around that average for the most part. Last year, however, over 70 percent of robbery incidents were armed robberies.

Year Simple Through Sept 9 Armed Through Sept 9 Total Through Sept 9 % Armed
2010 263 469 732 64.1%
2011 229 447 676 66.1%
2012 278 491 769 63.9%
2013 301 455 756 60.2%
2014 347 604 951 63.5%
2015 262 625 887 70.5%
2016 330 552 882 62.6%

Armed robberies through September 9 were down in New Orleans (625 in 2015 and 552 in 2016), but this is largely because of the shift in this robbery ratio. The shift can be seen in the below graph which measures the percent of robbery incidents marked simple vs. armed over 365 days since 2010.robbery-ratioIdentifying this changing trend is easy, explaining it is not. The most obvious explanation is the least satisfying, the changing ratio may just be normal random fluctuations in how crimes are committed.

Another likely culprit is improving response times in 2016. Armed robberies are more likely to be emergencies and thus more likely to receive faster response times and less likely to be marked ‘Unfounded’ (UNF) or ‘Gone on Arrival’ (GOA). Indeed 84.4 percent of 2016 armed robbery Calls for Service have been required an emergency response while only 38 percent of simple robberies have.

Indeed, plotting robbery incidents over 365 days marked RTF, UNF or GOA shows the impact slower response times last year had on driving up the percentage of armed robberies.

robbery-ratio-2

Robberies have a tendency to increase rapidly over the final three months of the year, so the story of 2016 robberies remains to be written. So far, however, it appears that they are down slightly from last year which is a positive trend.